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The Homogeneity of Variance Assumption

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1. Describe the general characteristics of a research study for which an independent-measures t would be the appropriate test statistics

2. What is measured by the estimated standard error that is used for the independent-measures t statistic?

3. Describe the homogeneity of variance assumption, and explain why it is important for the independent-measures hypothesis test.

11. A researcher is evaluating the pain-relief effectiveness of a new medication by comparing pain tolerance for a sample of n=10 people who receive the medication with pain tolerance for a sample of n = 10 people who received an inactive placebo. The scores for the placebo group produces a mean of M =38 with ss=150.
a. If the scores for the medication group have a mean of M=42 with ss=210, are the data sufficient to conclude that the medication has significant effect? Use a two-tailed test with ∞=.05.
b. In part (a), the medication group averaged 4 points higher than a control group, indicating that the medication had a 4-point effect. If the effect was 8 points, so the medication group had a mean of M=46 with ss=210, would the data be sufficient to conclude that there is a significant effect? Again, use a two-tailed test with ∞=.05.

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The solution describes the homogeneity of variance assumption and explains why it is important for the independent measure hypothesis test.

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